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I have a stock 80e with Transgo HD2. No idea how many miles are on it, was a junkyard engine.
Last year I had a shift cable failure that lead to a couple of neutral drops in the same day. Both times, every gear was forward afterwards. Reverse acted as a trans brake, and putting it in park, it would even push forward up the driveway onto the pin. Holding it at 2500 RPM or so in reverse and clicking it into neutral broke them apart.
I've had dozens of dyno and street pulls since then, and about 3000 street miles, no issues. Took it to the track, lost 2nd gear. Now it will not move when put into Drive. I pull the shifter down into 3rd and it drives OK. Sometimes putting it into reverse makes a ton of noise.
I could do a stock rebuild with some decent clutches and probably get a ton of miles out of it, but Obviously things are different when I'm at the track.
I just need it to last no more than a dozen passes a year at ~800whp.
What are the weak points that need to be addressed? I want to make sure I replace them while its apart. Searching lead me to a lot of VB mods, shaft replacement, etc which won't be done. There were a few good ideas floating around about what stock parts need replaced, but without any decent recommendations for a replacement.
rollerize the tailshaft and the hub, use a billet forward hub and a hardened input shaft and your good to 1000hp.
you can also add a clutch into the direct drum but not nessisary
you can do the dual feed mod also. the transgo kit alone should of been good to 750ft pounds of torque, uprading forward hub and input shaft should be good to 1000.
different kits require differnt mods and you cant interchage. im not sure what doing the dual feed mod would do with a transgo kit.
Sounds like your O/D Roller Clutch failed, This usually takes out the Overrun Hub & O/D Carrier.....Get a '91-'00 Overrun Hub, O/D Carrier & O/D Roller Clutch as it's larger in diameter & has larger rollers. Don't beat on this unit with the shifter in D4.
As stated above..... A Input Shaft & Forward Hub at your power level is a good idea as is rollerizing the Output & Forward Hub.
I would get rid of the TransGo shift kit, Plug the valve body where the pressure relief valve was installed.
Delete the 3rd & 4th Accumulators with a plate.
Run either a stock plate or a aftermarket plate with Accumulator passages deleted.
Internally dual feed the directs.
High Rate direct piston return springs, If the TransGo ones were installed....Use them.
I like using a Aluminum TH400 piston in the direct drum along with the Spring Retainer.
Drill a .035"-.055" hole at the edge of the direct drum under the piston.
Omit #5 & #6 checkballs if deleting the accumulators.
Sonnax 4L80E LB1 boost valve & PR spring.
Drill a "Lube to Line Bypass" in the pump cover if it wasn't done with the shift kit(.055")
The TransGo Intermediate Snap Ring is OK if it was installed?
TH400 Intermediate Spring Retainer, The 4L80E piece is flimsy! Reuse all 12 4L80E springs.
Check the Intermediate Sprag Inner & Outer Races for damage, Replace the Sprag with a new Borg Warner.
Replace the Low Roller Clutch with a Borg Warner.
Check for wear where the Input Shaft runs in the Forward Drum.
Replace ALL bushings!! You can install a Sonnax "No Walk" case bushing BACKWARDS if rollerizing the Output, Coat the OD of the bushing with red loctite, Seat it all the way & it will be the exact height you need to locate the bearing.....Yes, This defeats the design intent of the bushing, It's just easier for a first timer to not worry about bushing height.
Clock the Center Support Bushing correctly!
I like running a fluted Sun Gear Shaft bushing in place of the smooth bushing in the Overrun Hub/Sun Gear for better oil flow to the O/D Sun Gear Bearing. You will have to order this separate as a kit will only come with the 2 for the Sun Gear Shaft.
This unit is not picky when it comes to what Frictions are used, Stock Borg Warner's are a fine choice, I'm running Raybestos HD High Energy face grooved frictions in the Intermediate & Direct clutch packs & stock Borg Warner everywhere else with good results in my 4L80E.
If your TCC lock-up was working well, It was shifting, And the Line Pressure was good.....You don't need to do anything to the valve body besides a good cleaning & replace all the O-rings on the Solenoids & the 2 captured checkball capsules. Don't forget the 2 AFL Screen Filters.
This unit has FOUR end-play set locations! They need to be set....Let me know if you need help with this.
Sounds like your O/D Roller Clutch failed, This usually takes out the Overrun Hub & O/D Carrier.....Get a '91-'00 Overrun Hub, O/D Carrier & O/D Roller Clutch as it's larger in diameter & has larger rollers. Don't beat on this unit with the shifter in D4.
As stated above..... A Input Shaft & Forward Hub at your power level is a good idea as is rollerizing the Output & Forward Hub.
I would get rid of the TransGo shift kit, Plug the valve body where the pressure relief valve was installed.
Delete the 3rd & 4th Accumulators with a plate.
Run either a stock plate or a aftermarket plate with Accumulator passages deleted.
Internally dual feed the directs.
High Rate direct piston return springs, If the TransGo ones were installed....Use them.
I like using a Aluminum TH400 piston in the direct drum along with the Spring Retainer.
Drill a .035"-.055" hole at the edge of the direct drum under the piston.
Omit #5 & #6 checkballs if deleting the accumulators.
Sonnax 4L80E LB1 boost valve & PR spring.
Drill a "Lube to Line Bypass" in the pump cover if it wasn't done with the shift kit(.055")
The TransGo Intermediate Snap Ring is OK if it was installed?
TH400 Intermediate Spring Retainer, The 4L80E piece is flimsy! Reuse all 12 4L80E springs.
Check the Intermediate Sprag Inner & Outer Races for damage, Replace the Sprag with a new Borg Warner.
Replace the Low Roller Clutch with a Borg Warner.
Check for wear where the Input Shaft runs in the Forward Drum.
Replace ALL bushings!! You can install a Sonnax "No Walk" case bushing BACKWARDS if rollerizing the Output, Coat the OD of the bushing with red loctite, Seat it all the way & it will be the exact height you need to locate the bearing.....Yes, This defeats the design intent of the bushing, It's just easier for a first timer to not worry about bushing height.
Clock the Center Support Bushing correctly!
I like running a fluted Sun Gear Shaft bushing in place of the smooth bushing in the Overrun Hub/Sun Gear for better oil flow to the O/D Sun Gear Bearing. You will have to order this separate as a kit will only come with the 2 for the Sun Gear Shaft.
This unit is not picky when it comes to what Frictions are used, Stock Borg Warner's are a fine choice, I'm running Raybestos HD High Energy face grooved frictions in the Intermediate & Direct clutch packs & stock Borg Warner everywhere else with good results in my 4L80E.
If your TCC lock-up was working well, It was shifting, And the Line Pressure was good.....You don't need to do anything to the valve body besides a good cleaning & replace all the O-rings on the Solenoids & the 2 captured checkball capsules. Don't forget the 2 AFL Screen Filters.
This unit has FOUR end-play set locations! They need to be set....Let me know if you need help with this.
Thats some of the best info I've ever read, thanks!
Yes, the damage was caused in D4. I learned my lesson there.
merim123, I haven't done this yet. I have a quad turbo 4.8 corvette that I've spend the last couple of months messing with, and I've LS swapped 3 other cars in that time. Now I'm in need of a good TH400 for my corvette and my last quote was $2900. I'll get to it eventually.
Sorry for the dumb question but what happens when pounding on the 4l80e in D4 assuming we're talking about shifter in Drive? Why does this happen and obvious remedy is using 3rd as drive and 4th only when on hwy? I appreciate the feed back. I'll be checking in later this winter when I rebuild my 80e. Works well now at about 135,000k but it took some beating this summer and was doing some weird **** until I flushed it my self and switched to synthetic fluid. I think pump may be living on borrowed time however the fluid cleanse and swap made a world of difference. Since the WI winters are brutally long rebuilding and beefing up the 80e is on the agenda. Hoping to see 700-750 HP by spring with 250 of that being a 2 stage shot. I won't even waste my time pushing it that hard without out it ready to go or I'll spend a month down In the middle of summer hating life.
Sounds like your O/D Roller Clutch failed, This usually takes out the Overrun Hub & O/D Carrier.....Get a '91-'00 Overrun Hub, O/D Carrier & O/D Roller Clutch as it's larger in diameter & has larger rollers. Don't beat on this unit with the shifter in D4.
As stated above..... A Input Shaft & Forward Hub at your power level is a good idea as is rollerizing the Output & Forward Hub.
I would get rid of the TransGo shift kit, Plug the valve body where the pressure relief valve was installed.
Delete the 3rd & 4th Accumulators with a plate.
Run either a stock plate or a aftermarket plate with Accumulator passages deleted.
Internally dual feed the directs.
High Rate direct piston return springs, If the TransGo ones were installed....Use them.
I like using a Aluminum TH400 piston in the direct drum along with the Spring Retainer.
Drill a .035"-.055" hole at the edge of the direct drum under the piston.
Omit #5 & #6 checkballs if deleting the accumulators.
Sonnax 4L80E LB1 boost valve & PR spring.
Drill a "Lube to Line Bypass" in the pump cover if it wasn't done with the shift kit(.055")
The TransGo Intermediate Snap Ring is OK if it was installed?
TH400 Intermediate Spring Retainer, The 4L80E piece is flimsy! Reuse all 12 4L80E springs.
Check the Intermediate Sprag Inner & Outer Races for damage, Replace the Sprag with a new Borg Warner.
Replace the Low Roller Clutch with a Borg Warner.
Check for wear where the Input Shaft runs in the Forward Drum.
Replace ALL bushings!! You can install a Sonnax "No Walk" case bushing BACKWARDS if rollerizing the Output, Coat the OD of the bushing with red loctite, Seat it all the way & it will be the exact height you need to locate the bearing.....Yes, This defeats the design intent of the bushing, It's just easier for a first timer to not worry about bushing height.
Clock the Center Support Bushing correctly!
I like running a fluted Sun Gear Shaft bushing in place of the smooth bushing in the Overrun Hub/Sun Gear for better oil flow to the O/D Sun Gear Bearing. You will have to order this separate as a kit will only come with the 2 for the Sun Gear Shaft.
This unit is not picky when it comes to what Frictions are used, Stock Borg Warner's are a fine choice, I'm running Raybestos HD High Energy face grooved frictions in the Intermediate & Direct clutch packs & stock Borg Warner everywhere else with good results in my 4L80E.
If your TCC lock-up was working well, It was shifting, And the Line Pressure was good.....You don't need to do anything to the valve body besides a good cleaning & replace all the O-rings on the Solenoids & the 2 captured checkball capsules. Don't forget the 2 AFL Screen Filters.
This unit has FOUR end-play set locations! They need to be set....Let me know if you need help with this.
Im a pretty smart guy, and this **** looks like japanese
Beating on it in D4 puts everything on the overdrive roller clutch, it can't handle it and will fail
Again apologies for the dumb question. Assuming this applys to and only to, when in 4D While kicking it down a few gears @ WOT? From a dead stop it shouldn't matter correct? I just want to be clear. Thanks!
Again apologies for the dumb question. Assuming this applys to and only to, when in 4D While kicking it down a few gears @ WOT? From a dead stop it shouldn't matter correct? I just want to be clear. Thanks!
Doesn't matter. If it's in D4, the overrun clutches aren't applied.
D3 and lower apply them.
Good to know! and that guys is why I love and appreciate this forum so dam much! Little Tec things like that I’ll never figure out until I break something. You just saved a few seasons my 80e’s life.
05-19-2017, 10:12 AM
4L80e rebuild. Weakest links? 
